Subsidy policy optimization of multimodal transport on emission reduction considering carrier pricing game and shipping resilience: A case study of Shanghai port

To save energy and reduce carbon emissions, subsidy policies have been implemented to improve the competitiveness of railway and waterway transport in the multimodal transport system of port shipping. However, there is a lack of systematic research on the assessment of subsidy distribution with the consideration of shipping resilience and emission reduction. Disordered competition hinders the development of the multimodal transport market and also deters the achievement of carbon neutrality. To address these issues, this study proposes an optimized subsidy strategy with a bi-level subsidy decision-making model considering the pricing game between various carriers. Specifically, the amount of government subsidies is substituted into the upper model, and the carrier's pricing decision is obtained by solving the Nash equilibrium of the tripartite pricing game. An activity-based approach is used to calculate the emission reduction corresponding to the subsidy amount. The variance of the transport time is used to measure the resilience of transportation. Finally, the optimal subsidy strategy is obtained through quantitative comparison. This study employs the multimodal transport of containers based on Shanghai Yangshan Port as a case study. The sensitivity analysis discloses that the time value of goods and freight market conditions should raise more attention in the process of subsidy policy formulation. Moreover, the waterway carrier should try to improve resilience and reduce the risk of delay. This study innovatively considers the pricing game between highway, railway, and waterway carriers and provides a rational basis for the formulation of subsidy policies in multimodal transport through quantitative analysis.